Customer received some new stepper motors and found it very difficult to spin the shaft by hand. Naturally, the thought was the motors were ‘bad’. Normally, you can easily turn a stepper motor shaft by hand, and you can feel each of the 200 ‘detents’ as you rotate the shaft. However, these motors were very hard to turn by hand.
Well, the motor was just fine. Here’s the deal: you can see in the image how the wiring is stripped-back at the factory for testing. Depending on which wires happen to short-together during shipping and handling, the motor can be difficult to turn, or if all the wires are touching, the motor can’t be turned by hand! Separate the wires, and the ‘problem’ disappears.